Abstract :Chitosan is a naturally occurring cationic copolymer of randomly distributed D-glucosamine and N-acetyl-D-glucosamine units. It is derived from partial deacetylation of a linear chain polysaccharide chitin, a characteristic component found in the exoskeleton of crustaceans (shrimps, crabs, lobsters, etc.) and insects. Chitosan based delivery systems are biocompatible, biodegradable and can be chemically modified for targeting as well as for enhanced permeability through membranes. Due to its innate characteristics chitosan based systems show low immunogenicity and a good safety profile which translate into a widely applicable drug carrier [1]. Additionally, chitosan can form dissociable complexes with exogenous nucleic acids (pDNA, mRNA, siRNA, miRNA, antisense oligonucleotides, etc.), proteins, and several drugs owing to hydrophobic, hydrogenbonding, and electrostatic interactions [2]. Such interactions serve to protect the therapeutic agent from enzymatic degradation as well as other physiological factors owing to enhanced stability in the complex form [3-5].